Digital Predistortion at RF using Superconductor Electronics

HYPRES proposes to develop an RF-in-RF-out linearizer module that can be easily incorporated into existing radio systems for direct predistortion linearization of broadband (>100MHz), multi-carrier power amplifiers, over the 2MHz-2GHz range for the Joint Tactical Radio System (JTRS). This module will enable the use of higher-efficiency, but strongly non-linear, power amplifiers, as well as improve the spectral purity of the broadband transmit waveform. HYPRES will exploit fast (20-40GHz), high-linearity superconductor analog-to-digital and digital-to-analog converters and ultrafast digital logic circuits on an integrated multi-chip module to perform digital predistortion correction directly on the RF waveform. In Phase I, we propose to develop a new digital-RF predistorter that uses proportional, integral, and differential (PID) correction to compensate for rapid (10 GHz bandwidth) signal-dependent variations of the amplifier's non-linear transfer function, to achieve maximum suppression of intermodulation distortion. Neither narrowband analog RF electronics, nor slower semiconductor digital electronics, can achieve the necessary suppression. In Phase II, starting with a Phase I Option, we will design and demonstrate the PID digital-RF predistorter on a superconductor multi-chip module (MCM).